Re: typescript checking

[Hans Hagen <pragma@wxs.nl>]

dr. Hans van der Meer wrote:

> Hi Hans,
>
> On my "travels" through ConTeXt's fonthandling I got the following 
> result on typescript matching:
>     enter[xyz][][] and check[xyz][pqr][]
> does match.
>
> If I read the definition of  \dochecktypescript#1#2#3 well, this is 
> because an empty  argument #1 at once leads to a \donetrue. That makes 
> the checking of an empty argument equivalent to the checking with an 
> [all] key (but for the additional fact that [all] matches on both the 
> entered and the checked key). Then
>
> (enter[xyz][][] --- check[xyz][pqr][]) is equivalent with 
> (enter[xyz][all][] --- check[xyz][pqr][])
>
> Isn't this counterintuitive? I would have expected empty matching 
> nothing at all, or at most matching another empty argument. The point 
> is, I wanted to do a nice structured setup, something like:
>
> \starttypescript [A]  \usetypescript[A][AA]  
> \usetypescript[A][AB]\stoptypescript
> \starttypescript [A][AA] ...
> \starttypescript [A][AB] ...
> etc.
>
> Now [A] matches[A][AA] (i.e. [A][][] matching [A][AA][]) and this 
> doesn't work.
> It has the addtional problem that for example typescript [pos] in 
> type-pre.tex (by calling \setupbodyfont[pos]) has a sub-typescript 
> [all][times,helvetica,courier][texnansi] that now will match 
> typescript [A][][]. That was not meant to be the case! At least not by 
> me when I wrote the typesciprt. But if the file containing [A][][] is 
> in the searchpath it will be processed in each round. In some cases it 
> even can lead to an infinite recursion of typescripts.
>
> Setting up things from "back to front" ([AA}[A] etc.) alleviates some 
> of the problems, but does not stop the unwanted occasions where [A] 
> matches [all][other_things].
>
> Do I have it all wrong?
> Thanks to those who will take the trouble to look into this matter.
> Hans van der Meer

Ok, the next release will have: 

\usetypescriptexact

where empty defaults to a false match, so that you can play a bit with that alternative. I'll send you the file.  

Hans  

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